Aberrant expression of angiopoietins-1 and -2 and vascular endothelial growth factor-A in peri-implantation endometrium after gonadotrophin stimulation
Authors: Lee, Yin-Lau; Liu, Yunao; Ng, Pak-Yiu; Lee, Kai-Fai; Au, Chak-Leung; Ng, Ernest Hung-Yu; Ho, Pak-Chung; Yeung, William Shu-Biu
Source: Human Reproduction, Volume 23, Number 4, 27 April 2008 , pp. 894-903(10)
Publisher: Oxford University Press
Ovarian stimulation affects normal endometrial development. The expression of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and vascular endothelial growth factor-A (VEGF-A) and the vascular state in the peri-implantation endometrium in women with natural and gonadotrophin-stimulated cycles were compared.
The expression of these angiogenesis-associated molecules in endometrial biopsies, collected on Day 7 after human chorionic gonadotrophin injection or luteinizing hormone surge in stimulated or natural cycles respectively, or at mid-luteal phase of women undergoing diagnositic laparoscopy, were analysed.
Women with gonadotrophin-stimulation had lower Ang-1, but higher Ang-2, mRNA and protein expression (P < 0.05), and increased concentrations of von Willebrand factor (vWF) and blood vessel density than those with natural cycles (P < 0.05). Although stimulated cycles had higher VEGF-A mRNA expression (P 0.023), VEGF-A protein expression was similar between the groups. Lower Ang-1/Ang-2 but higher Ang-2/VEGF-A mRNA ratios (P 0.025) were found after gonadotrophin-stimulation. The ratios were negatively (P < 0.001) and positively correlated (P < 0.001) with estradiol levels, respectively. Cyclical changes in Ang-1 and Ang-2, but not in VEGF-A expression were noted.
The decreased Ang-1 concentration and Ang-1/Ang-2 ratio and the increased Ang-2 concentration, with the increased vWF concentration and blood vessel density, in stimulated cycles suggests advanced endometrial angiogenesis after gonadotrophin-stimulation.
Document Type: Research Article
Publication date: 2008-04-27
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